Testing arrangement for power circuits



Nov. 15, 1932. P. SPORN ET AL TESTING ARRANGEMENT FOR POWER CIRCUITSOriginal Filed Sept. 17, 1924 2 Sheets-Sheet l 7 2 W W 7 z m m 1 M M Wnm n m l /W m mw m m m fi:

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Nov. 15, 1932. P. SPORN ET AL 1,887,962

TESTING ARRANGEMENT FOR POWER CIRCUITS Original Filed Sept. 17, 1924 2Sheets-Sheet 2 Tel/ CO/L Patented Nov. 15, 1932 UNITED STATES PATENTOFFICE rmLi'r srois n, or BROOKLYN, AND HENRY n. FREITAG, or LYNBROOK,NEW YORK,

ASSZGNORS T0 minors-410 recesses COMPANY, INC., on NEW YORK, 1v. 2., Aconronn'rron on NEW YORK TESTING KRRANGEIVIENT FUR POWER CIRCUITSOriginal application filed September 17,

This is a division of our co-pending application Serial Number 738,272,filed Septem ber 17, 1924. The object of the invention is to provide anarrangement for testing. relays, meters or similar apparatus associatedwith the power circuits of power transmission and distribution systemswithout disturbing the operating circuits of the system and with aminimum impairment of the safetyand s1m li ity of the system.

According to the invention a relay or meter calibrating switch isprovided by means of which the contact circuits and operating c011circuits of the relay or meters are separated from the normal powercircuits connected to these contacts or operating coils and are thrownover to testing busses by means of which any predetermined currentorvoltage may be applied to the operating coils, and the operation orregistration of the relays or meters observed. By the arrangement of theinvention, the load adjustmentand testing of a relay can be made whilethe relay is in operating position, the relay being thrown intothe'testing position only after the testing apparatus is set, thuscutting down to a minimum the loss of the protective value of therelays. The arrangement has also com bined therewith a lamp forindicating the condition of the relay circuits and means for assuringthat the relay is normally left inethe' operating position.

The original application is directed to, and claims, the special testswitch used in the test arrangement or" our invention describedhereinafter. The present application directed to the general arrangementfor-the improved and simplified testing of relays or meters and is notlimited to any particular type of switch.

The object-sci the invention 'will be best understood from the followingdescription of an exemplitication thereof, reference being had to theaccompanying drawings wherein Fig. 1 is an end section view of a'testingswitch used inthe arrangement of the invention';

Fig. 2 is atop plan View of a switch with the cover removed;

Serial Ho. 738,272. Divided and this application "filed December 5,1930. Serial No. 500,180.

of the to 4 comprises a box-like container having side walls 10, 11 andpanel members 14,15, a bottom wall 12, anda cover wall 13; .On theopposite walls 10, 11 are mounted-sets of rectangular lugs 16 secured inthe walls by means-of threaded-studs 17. The lugs '16 carry pairs ofcontact fingers 19 which are spaced from each other, the spacing beingadjust-ably fixed by screws 20. Between each set of lugs; 16 are mountedadditional central lugs2l secured to the walls 10, 11

by means of threaded studs 22. The central lugs 21 carry pairs of ears23 supporting pivot pins 24 on which .are pivotally mounted'contactblades 25 for'movement to establish electrical connection between thecentral lug members 21 and with the contact fingers lying on either oneorzthe other side of the central lug members. The contact blades 25 aresoshaped and arranged that in their intermediate position they engagethe contact fingers lying on both sides-of the central lug members, asshown in Fig. 1.; The several bladescooperating with the con tactmembers mounted on the opposite walls 10,311 are pivoted to one oranotherposition by means of a shaft 26 extending longitudi nally throughthe box between the walls 1O, 11. The shaft carries blocks 27 providedwith transverse slots 28 adaptedito fit over the contact blades 25. theblocks transversely to the slots 28 and engaging slots 30 formed in thecentral part of the blades 25, transmit the movement :of the blocks tothe blades so that upon turning the shaft26 one way or the otherptheblades 25 are pivoted from one contact position to the other. l

The] box-like structure containing the switch mechanism is mounted onthe b'aclrof a panel board 31 which is provided with an Pins 29 mountedin ion ly opposed slots 33. A suitable key 34 is adapted to be insertedthrough the opening in the escutcheon plate, the key havlng a borefitting the end of the shaft 26 and having slots adapted to engage pins35 mounted on the shaft, so that upon rotating the key the shaft isrotated. The key is likewise provided with registering pins 36 arrangedto fit the slots 33 in the escutcheon plate, so that the key may beinserted and'taken out from the escutcheon plate opening only in theposition where the registering pins 36.

register with the slots 33. The position of the slots in the escutcheonplate 33 is so chosen that when the key is in the position in which itcan be taken out from the escutcheon plate, the shaft 26 of the switchis turned to a position where the blades establish the connections forthe normal operation of the apparatus in the station, this positionbeing indicated on the escutcheon plate by the letters OPER or othersuitable designation. After the key isinserted, it may be turned tobring the contact blades'to the opposite switching position, the switchbeing then in the testing position corresponding to the designation onthe escutcheon plate indicated by the word TEST.

The only portion ofthe switch mechanism exposed to view when theapparatus is mounted in position is the face of the escutcheon plate 32upon which the designations TEST and OPER appear. When the key isinserted into place the/switch contacts are in the position in which thenormal operating circuits are established. In order to establish thetesting circuits, the key is turned to the position indicated by theword TEST. This rotatesthe shaft 26 with the blocks 27 and causes thecontact blades 25 to engage the contact fingers opposite those withwhich they are in engagement in the operatingposition.

The testing of the relays is accomplished by sending current through theoperating coils of the relays and timing or testing the relay operation.

A typical testing arrangement illustrating the testing switch shown inFigs. 1 to 4 as used in accordance with our invention is struction shownin Figs. 1 to 4. Lamps 49, 49 may be provided for indicating thecondition of the relay circuits. The relays 43, 43 are provided withactuating coils 50, 50 and tripping contacts 51, 51, connected toenergizethe tripping coil 44 and trip the circuit breaker in case therelay is actuated by an overload through the associated currenttransformer 42, 42. The watthour meter measures the amount of powerflowing through the feeder.

With the arrangement shown in Fig. 5, if it is desired to test relay 43,a testing apparatus'53 is connected to its busses C C R R and thecircuits of the testing apparatus are adjusted to be ready for the test,while the test switch is left in its normal operating position shown inthe drawings. When all adjustments have been made ready, the test switchis thrown to the TEST position and the relay tested in a short time,whereupon the test switch is immediately thrown back into the operatingposition. While thus testing relay 43, the circuits of relay 43 and ofthe watthour 'meter 46 are left undisturbed andwi-ll continue tooperate. Similarly, relay 43 or watthour meter 46 can each be testedwithout disturbing the other meters and relays and the associatedcurrent transformer circuits.

As seen in Fig. 5, thetest switches 47, 47,

and 48 are all shown in the normal operating positions; The testingswitches 47 and 47 have each six simultaneouslyactuated double-poleswitch units 47a to 47 f and 47 'a to 47 'f, respectively','and testswitch 48 has four simultaneously actuated double-pole switch units 48ato 48d.

In the position shown in the drawings, the various switch units ofswitches 47 and 48 establish connections as follows: Switch units 47aand 47 Z) connect the tripping contacts 5l of relay 43 to the energizingcircuit of tripping coil 44 so that on closure of the tripping contacts51 the circuit breaker 41 is tripped. Switch'47c establishes anenergizing circuit from the source 45 for lamp 49 so as to maintain itilluminated as long as switch 47 is in operating position, the circuitbeing opening at unit47e when the switch 47 is thrown into the oppositetesting position.

Switch units 4761, 47c and 47 fconnect the two tuating coil50' and thesecond current coil of the watthour meter 46.

'lVhen the testing switch 47 for testing relay 43, for instance, isthrownto, the opposite testing position, the various switch units 47a to47 f establish inthe new positions the fol lowing connections The switchunits 477a and 47b disconnect the tripping contacts 51 of relay 50 fromthe energizing circuit of circuit breaker tripping coil 44 and connectthe tripping contacts 51 to the test busses C 0 leading to the test set53. The switch units 4'?(Z and 476 disconnect the relay actuating co l50 from the closed circuit of the current transformer 42 and connect therelay coil 50 to the test busses R R leading to the test set 53.Simultaneously, switch unit 47; completes the closed circuit for thecurrent transformer over the current coil of the watthour meter 46,bridging the now open connections overswitch units 47d and 476 thatformerly included relay coil 50 in the closed circuit. In going fromoperating to testing positions, there is at all times maintained acomplete closed circuit around the current transformer coil 42, becausethrough the special construction of the testing switches shown in Figs.1 to 4, the switch units when in intermediate position have the bladesinengagement with all of the cooperating contact fingers, so that thenew closed circuits are established at the contact fingers that comeinto engagement withthe blades before circuits are broken at the contactfingers that become disengaged from the contact blades.

Thus, with the testing switch 47 in testing position, the watthour meter46 is energized as in normal operation, and the current transformer 42is closed-circuited, but the actuating coil 50 and the tripping contacts51 of the relay are disconnected from their normal operating circuitsand are connected to the testing set-53 by means of which the action ofthe relay may now be conveniently checked and tested without disturbingthe operating circuits and apparatus at the station. After the testisthrough, the throwing of the testing switch 47 to operating positionrestores the normal operating connections of the relay 43, again withoutdisturbing the closed circuit of the current transformer 42 and theenergizationof the watthour meter 46.

In a similar way relay 43 that is operated by current transformer 42' ofthe other feeder phase may be tested by means of testing switch 47without disturbing the closed circuit of the current transformer and theenerg'zation of the watthour meter 46.

If the watthour meter 46 is to be tested and the meter testing switch 48is thrown from the normal operating position shown in the drawings tothe opposite testing position, the various switch units 48a to 48destablish the following connections: Switch units 485 and 48d bridge theconnections leading from the closed circuits of the two currenttransformers 42 and 42 to the two current coils of the watthour meter46, respectively, and simulbus leading to one of three meter testingterminals 54, the other two meter testing terminals being permanentlyconnected to the leads from the switch units 48a and 48d to the watthourmeter current coil terminals. A

standard testing meter may be connected to the meter testing terminals54 and the meter tested-while the testing switch 48 is in testingposition. 1

After completion of the test the watthour meter 46 may be again quicklyconnected in its normal operating circuits by throwing the testingswitch 48 to the operating position. Because of the special'constructionof-the switch units and the intermediate bridging of the switchcontacts,vthe .transitionsbetween the operating and testing positionareeifected without disturbing the closed circuits of the currenttransformer 42, 42 and the operating circuits of the relays 43, 43', orany other parts of the operating system.

The invention may be embodied in the form of many other arrangementsthat will suggest themselves to those skilled in the art and it isaccordingly desired that-the ap pended claims be given a broadconstruction commensurate with the scope ofthe invention within the art.

We claim: V

1. In a testing arrangement for power stationapparatus, analternating-current power line, a current transformer energized by saidline, an auxiliary apparatus associated with said power line adapted tobe connected in a closed circuit with said current transformer to beenergized thereby, a testing device for said auxiliary apparatus, andswitch means for completely disconnecting the leads of said auxiliaryapparatus from its normal operating circuits and said currenttransformer and connecting said auxiliary apparatus to said testingapparatus,-said switch means being so arranged that on being actuatedfrom operating to testing position a new closed circuit for said currenttransformer is completed bridging the connections leading to saidauxiliary apparatus prior to opening of said lastnamed connections, andon being actuated back to normal'operating position said switch meansrestoring the normal closed circuit of said current transformer throughsaid auxiliary apparatus before opening said bridging closed circuit.

2. In a testing arrangement for power 'sta tion apparatus, analternating-current power line, a current transformer energized by saidline, a plurality of auxiliary apparatus associated with said line, eachof said auxiliary apparatus having a current element adapted to beconnected in series with each other to form a closed circuit with saidcurrent transformer to be energized thereby, a testing device for one ofsaid auxiliary apparatus, and switch means for disconnecting saidauxiliary apparatus from its normal operating circuits and said currenttransformer and connecting said auxiliary apparatus to saidtestingapparatus, said switch means being so arranged that on being actuatedfrom operating to testing position the connections to the currentelement of the auxiliary apparatus to be tested are bridged and a closedcircuit for the current transformer and the current element of the otherauxiliary apparatus is completed prior to opening of the closed circuitconnection to the current element of the apparatus to be tested, and onbeing actuated from testing position to operating position said switchmeans restore the normal closed circuit connections of said transformerprior to opening of said bridging closed circuit.

3. In a testing arrangement for power station apparatus, a three-phasealternating-current power line, a circuit breaker for said power line, apair of current transformers associated with two phases of said powerline,

a tripping circuit for said circuit breaker, a

tripping relay having a coil connected in a closed circuit with one ofsaid current transformers for actuating said tripping circuit, a secondtripping relay having a current coil connected in a closed circuitconnected with the other of said current transformers for actuating saidtripping circuit, atesting device for testing either one or the other ofsaid relays, and testing switch means for each of said relays fordisconnecting the associated relay from its normal operating circuitsand connecting the relay to said testing apparatus for testing the sameindependently of the power circuit, said testing switch means being soarranged that on being actuated from operating to testing position a newclosed cir-" cuit for said current transformer is completed bridging theconnectionsleading to the current coil of the associated relay prior tothe opening of said connection, and on being actuated from testingposition to operating position said switch means complete the normalclosed circuit between the current coil and the associated currenttransformer priorto opening of the bridging circuit.-

4;. In a testing arrangement for power station apparatus, analternating-current power line, a current transformer energized by saidline, a relay associated with said power line and having a current coiladapted to be connected in a closed circuit with said currenttransformer to be energized thereby, a meter device having a currentelement adapted tobe connected in series with said current coil in theclosed circuit of said current transformer to energize said meterdev1ce,a testing device for said relay, and switch means for dis- Iconnecting said relay from its normal operating circuits and connectingthe same to said testing apparatus, said switch means being so arrangedthat on being actuated from operating totesting position a new closedcircuit for said current transformer and said current element of themeter device is completed bridging the connections leading to saidcurrent coil prior to the opening of said connections, and on beingactuated from the testing position to the operating position said switchmeans restore the normal closed circuit including serially said currentcoil, said current element and said current transformer prior to theopening of said bridging circuit. i

5. In a testing arrangement for power station apparatus, a three-phasealternatingcurrent power line, a pair of current transformers associatedwith two phases of said power line, a pair of relay devices having eacha current coil, a meter device having a pair of current elements, thecurrent coil of one relay device and the current element of the meterdevice being connected in a closed circuit with one current transformer,and the other current element of said meter and the current coil. of theother relay being con- 'nected in a closed circuit with the othercurrent transformer, a testing device for said relay devices, and switchmeans for each relay device for disconnecting said relay device from itsnormal operating circuits and connecting it to said'testing apparatus,said switch means being so arranged that on being actuated fromoperating to testing position a closed circuit for said currenttransformer and the associated current element of the meter is completedbridging the connections leading to thecurrent coil-of the associatedrelay prior to the opening of the connections to said current coil, andon'beingactua-ted from testing position to operating position saidswitch means restore the normal closed circuit of the associated currenttransformer prior to the opening of said bridging connections. p

In testimony whereof, we have hereunto subscribed our names, this 4thday of December, 1930.

PHILIP SPORN. HENRY D. FREITAG.

